Heat exchange organization



April 18, 1961 Filed Sept. 22, 1958 E. C. WITZKE HEAT EXCHANGE ORGANIZATION 4 Sheets-Sheet 1 FIG. I

INVENTOR.

ERNEST C. WITZKE whozw ATTORNEY April 18, 1961 E. c. WITZKE 2,980,083

HEAT EXCHANGE ORGANIZATION Filed Sept. 22, 1958 4 Sheets-Sheet 2 45 INVENTOR.

ERNEST G. WITZKE FIG. 2 PM ATTORNEY April 18, 1961 E. c. WlTZKE HEAT EXCHANGE ORGANIZATION 4 Sheets-Sheet 5 Filed Sept. 22, 1958 FIG. 3

FIG. 4

ATTORNEY April 18, 1961 E. c. WITZKE 2,980,083

HEAT EXCHANGE ORGANIZATION Filed Sept. 22, 1958 4 Sheets-Sheet 4 Q I r- LO N fimmm ras Q l y}aawmwrfi $0 n s w r "'1 Q Q q N FIG.5

:73. S; INVENTOR.

ERNEST c. WITZKE ATTORNEY United States Patent 2,980,083 HEAT EXCHANGE ORGANIZATION Ernest C. Witzke,.Bayside, N.Y., assign'or to Combustion Engineering, Inc., New York, N.Y., a corporation of Delaware Filed Sept. 22, 1958, Ser. No. mass 6 Claims. or. 122-477 This invention relates generally to modern high capacity steam generators and is particularly concerned with the construction of the gas pass of such a steam generator and within which is disposed heat exchange surface generally in the form of the economizer section of the steam generator and a steam heater.

The gas pass to which reference is being made is in the form of a large upright duct that receives hot combustion gases at its upper end from the furnace with these gases, passing down through the gas pass over heat exchange surface located therewithin and discharging from the lower end of the gas pass. Prior to applicants improved construction of this invention it was the general practice to provide large plates adjacent the economizer which is located within the gas pass at the lower end, with this region being generally referred to as the low temperature zone. These plates form the wall of the gas pass at this zone and in addition to these plates various amounts of refractory and/or insulation was required to protect the casing of the gas pass. This construction was extremely difficult to maintain in order because of dilferential expansion problems and it was also diflicult to assemble. I

Accordingly, a constant search has been conducted to provide an improved construction which will overcome the difficulties and shortcomings of that heretofore employed. It is desirable to have this upright gas pass fully cooled from its upper region to a location below the economizer, i.e., have heat exchange tubes extend along and line the inner surface of the gas pass. It is also desirable to have complete backing of the fluid-cooled inner surface of the gas pass with a gas tight casing and to Provide full support for the economizer elements and the gas pass walls" from the fluid cooling tubes.

These objectives are realized with applicants invention wherein the economizer is made in two sections and the tubes of the economizer extends along a pair of opposed walls of the gas pass which is generally rectangular in transverse section. The supply headers for the economizer are generally below the economizer sections and are adjacent and parallel with this pair of opposed walls. One of the sections of the economizer is positioned above the other and to form these sections alternate tubes, or

some such similar arrangement, are bent from the plane of the wall to form the tube bundle of each section and then returned to the plane of the wall. The superheater heat exchanger that is located above the economizer in the gas pass, is supplied from heaters that are at the same elevation as the supply headers for the economizer-{but that are adjacent the other two opposed walls of the duct. These headers receive steam from tubes that extend down from the upper end of the gas pass along the inner surface of these other opposed walls. The economizer sections are supported from structural supports that are connected to these supply tubes for the" superheater and since the economizer will then move vertically in ac cordance with" the expansion and contraction of these super-heater supply tubes, which is'different than the expansion and contraction of the economizer tubes, the

2,980,083 Patented Apr. 18, 1961 construction of the economizer is such as to accommodate the necessary difierential movement that will take place. The outer wall structure of the gas pass, which includes insulation, sheet or plate type casing sections, stiffener members and the like, is all supported from the tubes that extend vertically along the inner surface of the walls of the gas pass.

It is an object of this invention to provide an improved construction for use in vapor generators and particularly with relation to the gas pass through which combustion gases from the furnace of the generator pass and traverse heat exchange surface located therewithin.

Other and further objects of the invention will become apparent to those skilled in the art as the description proceeds. I

With the aforementioned objects in view, the invention comprises an arrangement, construction and combination of the elements of the inventive organization in such a manner as to attain the results desired as hereinafter more particularlyiset forth-in the following detailed descrip tion of an illustrative embodiment, said embodiment being shown by the accompanying drawing wherein:

Fig. 1 is in the nature of a vertical sectional View, somewhat diagrammatic, of a steam generator incorporating the present invention; a

Fig. 2 is an enlarged and more detailed vertical section of the gas pass that receives the combustion gases issuing from the furnace, with this view showing the tubes of the wall structure of the gas pass with a portion of the outer structureof the wall being removed;

Fig. 3 is a fragmentary sectional view of the gas pass wall at the location of line 33 of Fig. 2 with this View showing the tube disposition at this location and also showing the outer wall structure;

Fig. 4 is a view similar to the Fig. 3 but at a location of line 4- .-4 of Fig. 2;

Fig. 5 is a sectional view taken from line 55 of Fig. 2 and showing the economizer at right angles to the showing in Fig. 2; v V

Fig. 6 is a fragmentary sectional view similar to that of Fig. 3 but taken from line 66 of Fig. 5;

Fig. 7 is a view similar to that of Fig. 6 but taken from the location of line 7--7 of Fig. 5.

Fig. 8 is a vertical fragmentary sectional view showing details of construction with regard to the secondary wall structure; and,

Fig. 9 is a sectional view taken along line 9-9 of v Fig. 8.

Referring now to the drawings, wherein like reference characters are used throughout to designate like elements, the illustrative and preferred embodiment of the invention depicted therein, includes a furnace 10 in which fuel is burned for the generation of steam as in water tubes 12 lining the walls of the furnace. The mixture of steam and water is discharged into a separator drum 14 with the steam here being separated and passing from the drum to conduit 16. Combustion gases generated in furnace 10 pass upwardly through the furnace and into the upper end of gas pass 18 with the gases passing down through this gas pass and out the lower end thereof. Located within this gas pass 18 is the economizer 2t and the superheater section 22 with this superheater section generally being termed the low temperature superheater and with there being provided at the upper end of furnace 12 a high temperature superheater section 24 as is common practice.

Feed water is supplied to the economizer 20 through the inlet headers 26 and 28 with header 26 being adjacent to and extending transversely of wall 30 of gas pass 18 while header 28'is similarly located with respect to wall 32 of the gas pass. The tubes that form the economizer are" connected at their lower ends with these respective headers and as best shown'in" Fig. '5; extend upwardly from these headers. Economizer 20 is divided into two sections 34 and 36 with every other tube (or a similar arrangement of uniformly spaced tubes) extending along walls 32 and 30 forming these sections, with the tubes identified as 38, that are connected with headers 28, and identified as 40, that are connected with header 26, forming section 34 and with the tubes 38 and 44) being sinuously bent and positioned in sidc-by-side relation in section 38 as shown. Section 36 of economizer 20 is formed by the remaining tubes connected with header 28 and identified as 42 and connected header 26 and identified as 44 with these tubes also being sinuously bent and disposed in side-by-side relation in this section 36. The tubes 46 after forming 1 part of economizer section 34 extend up along the inner surface of wall 32 while the tubes 33 extend along the inner surface of wall 30, and similarly, tubes 44 of economizer section 36 extend along the wall 32 and tubes 42 extend along wall 30.

As an example of a typical layout, there may be 76 economizer tubes connected along each of these headers 26 and 23 with alternate tubes throughout the length of each of these headers making up two economizer sections, thus tubes identified as 38 and 40 which make up economizer section 34 will comprise a total of 76 tubes spaced across the gas pass and tubes identified as 42 and 44 and which make up economizer section 36 would also have 76 tubes spaced across the gas pass. At the ends of each of the economizer sections 34 and 36 there will be only half as many tubes lining the inner surface of the walls 30 and 32 as at the location between these economizer sections and above the economizer. This is shown in Figs. 6 and 7 with Fig. 6 showing the tubes lining the Wall of the gas pass opposite economizer section 34 and with these tubes being provided with fins to generally fill the space between the tubes. Fig. 7 shows the disposition of the tubes adjacent the wall of the gas pass at the location between economizer sections with the tubes then being tangent. It will be understood that this is only representative of various arrangements that may be provided with the essential requirements being that the economizer tubes line the inner surface of Walls 30 and 32.

The economizer tubes that extend up along the walls 30 and 32 are connected at their upper ends with one of the headers 70, there being two such headers one above each of the supply headers 26 and 28. Feedwater enters the headers 26 and 28 through the conduits 37, flows through the economizer tubes to headers 70 and then through conduits 39 to drum 14.

Steam is conveyed from drum 14 through conduit 16 to the distribution header 46 and from this header the steam is conveyed to the superheater inlet or supply headers 48 and 50 through supply tubes 52 and 54, respectively. Headers 48 and 58 are on the same level as the economizer inlet headers 26 and 28 and may be secured thereto and header 4-8 is adjacent to and extends transversely of wall 56 of the gas pass while header 5th is similarly disposed with relation to wall 58 of the gas pass. Supply tubes 52 and 54, which are uniformly spaced along the length of distribution header 46 and accordingly supply headers as and 50, extend down along the inner surface of walls 56 and 58, respectively. The spacing of these supply tubes.

may be varied as desired from a generally tangent relation to a substantially spaced relation.

In the illustrative embodiment the tubes 52 and 54 are spaced somewhat with Fig. 3 showing the relative disposition of the tubes 52 and with the space between adjacent tubes being filled with a suitable fin secured to the tubes.

The superheater section 22 is made up of a tube bundle that is formed of sinuously bent tubes that extend back and forth across the gas pass as shown in Fig. 2 with some of these tubes, as for example, alternate tubes across the width of the gas pass, and identified a560, extending down past the economizer in an adjacent relation to the inner surface of wall 58 and connected with header 50 while the remaining tubes, identified as 62, extend in similar relation with wall 56 and are connected with header 48. Since supply tubes 52 and 54 are spaced, these tubes 60 and 62 may be positioned between these spaced tubes with the fins being removed for this purpose and with Fig. 4 showing the tubes 62 interposed between tubes 52. The tubes of superheater section 22 are connected at their upper ends with header 64, which, in turn, is connected with the high temperature section 24 of the superheater.

The tubes lining the four walls of'the gas pass 18 are supported from their upper end by suitable structural supports, such as tube hangers 66 that are supported from structural members 68. In the case of the economizer tubes that extend up along the walls 30 and 32, this support is efiected by hanging from these supports 66 the economizer headers 70 to which the upper ends of these tubes are connected. Thus the gas pass or the walls thereof are supported from above and expand downwardly.

The support for the economizer sections 34 and 36 is derived from the I beams 72 that extend between walls 56 and 58 of the gas pass with these beams being supported on lugs 74 that are secured to the superheater supply tubes (Fig. 2). Extending up from these I beams are support members 76 (Fig. 5) that are formed to receive the laterally extending tube runs and are secured to these runs. The upper tube run 78 in each of the economizer sections is free of these support members 76 so that it may flex or bend as required to accommodate movement between the tube bundles that make up these economizer sections and the walls 30 and 32 upwardly along which the economizer tubes extend. This is necessary since the economizer tubes lining walls 30 and 32 will expand a different amount than the superheater tubes lining the walls 56 and 58 and since economizer sections 34 and 36 are supported from the superheater supply tubes they will move vertically with them and accordingly move relative to the walls 30 and 32.

The inner surface of the four walls of the gas pass 18 is lined with fluid cooled tubes, as described, and the outer structure of the wall which may take a variety of forms, is supported from these tubes. The construction of this outer wall portion may be in accordance with that shown and described in my Patent 2,773,487, issued December 11, 1956, with this being a desirable construction since it provides for the necessary difierential expansion of the duct walls. Fig. 8 shows a construction of an outer wall wherein the fluid cooled tube line the inner surface of the wall and are backed by a pressure tight casing 81] that extends between the vertically spaced laterally extending channels 84. Channels 84 extend across the wall and are secured to the tubes and lugs 82 are secured to this channel and extend outwardly therefrom. These lugs together with channel clips 85 form a stirrup connection that supports the stilfening buc'kstay 86 with this stirrup connection providing for lateral movement between the buckstay and the tubes. Inbetween buckstays 86, which are spaced at vertical locations throughout the length of the wall, extends plate members 88 and intermediate these members 88 and the casing 83 is disposed suitable insulation 90. It will be understood that this is only one of a variety of possible constructions of the outer wall components that may be employed with the inventiom'the details of the outer wall components not forming a part of the invention other than to provide a pressure tight casing and to provide a construction that is supported from the tubes.

With the present invention full cooling of the gas pass 18 at the economizer area is had with the cooling surface being completely backed by a pressure tight skin casing and with the entire gas pass and economizer being supported from the cooling tubes which are, in turn, supported at the upper end of the gas pass.

While I have illustrated and described a preferred embodiment of my invention it is to be understood that such is merely illustrative and not restrictive and that variations and modifications may be made therein without departing from the spirit and scope of the invention. I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes as fall within the purview of my invention.

What is claimed is:

1. In a vapor generator an upright gas passageway of rectangular transverse section and adapted to have a stream of hot combustion gases pass downwardly therethrough, a superheater heat exchanger in said passageway as well as an economizer heat exchanger below said superheater, longitudinally extending tube means carrying steam for superheating lining a pair of opposed walls of the passageway and extending from the upper end thereof to a location below the economizer heat exchanger, means effectively connecting these tube means to the superheater heat exchanger, longitudinally extending economizer tube means in side-by-side relation lining the inner surface of the other two opposed walls of the passageway throughout this same length, alternate of these tubes from at least one wall of this latter pair of opposed walls being bent from the plane of the wall and formed in serpentine configuration to extend back and forth across the passageway thereby forming a tube bundle with these tubes returning to the place of one of the walls and extending therealong, fin means secured to the remaining tubes lining the wall from which the tubes are bent to form the bundle and at the location of the bundle to fill the space left by the bundle forming tubes, means supporting the tubes extending along the walls of the passageway from their upper ends, and outer wall structure supported from these tubes.

2. A vapor generator for generating superheated vapor comprising in combination an upright furnace into which fuel is introduced and burned and which has its exit for combustion gases at its upper end, a gas passageway of rectangular transverse section extending down alongside said furnace and communicating at its upper end with the furnace outlet, a pair of opposed walls of the passageway having tubes extending along the inner surface longitudinally thereof to a predetermined distance from the upper end thereof and connected at their .lower ends to headers adjacent to and transversely of the respective walls, a group of sinuous bent tubes within said passage at a given distance above said headers, said tubes having portions extending parallel with and adjacent to the tubes on said opposed walls and connected with said headers, means for supplying steam to and conveying it from said group of tubes, tubes lining the inner surface of said other pair of opposed walls throughout said predetermined distance and connected at their lower ends with headers adjacent to and transversely of the respective other walls at the horizontal locations of the first mentioned headers, alternate of these last named tubes, having portions horizontally bent inwardly of the passage to form an economizer tube bundle in the passage below said sinuously bent tubes but above said headers with the remaining tubes along these walls being finned at the location of the tube bundle to fill the space left by the bundle forming tubes, means supporting the tubes extending down along these walls from their upper ends, and outer wall structure sup ported from these tubes.

3. The organization of claim 2 including means sup porting the economizer tube bundle from the tubes extending along the first mentioned pair of opposed walls with the tube portions forming the economizer tube bundle having flexible portions effective to accommodate differential movement between the tube bundle and the wall along which the tubes that form the tube bundle extend.

4. An improved superheater and economizer arrangement comprising in combination a vertical gas passageway of rectangular transverse section to receive gases from the furnace of a vapor generator for flow downward there through, a superheater tube bundle in said passageway comprised of sinuously bent tubes in side by side spaced relation across the passageway and extending between a pair of opposed walls of the passageway, an economizer in the passageway below the superheater and comprised of two sections spaced one above the other and each comprised of parallel side by side tube elements sinuously bent and extending transversely of the passageway between the other pair of opposed walls, headers adjacent to and transversely of each of the walls of the passageway at Ya location below the economizer, the tube elements of the economizer being portions of tubes that are connected with the headers adjacent said other pair of opposed walls and which extend up along the inner surface of the respective walls to the upper end of the passageway with generally half of these tubes being bent from the plane of each wall to form each economizer section and returned to the plane of the wall and with the tubes of each wall that form one section of the economizer being uniformly intercalated among these forming the other section and with the tubes that form one section lining the furnace wall adjacent the other section, superheater supply tubes extending down along the inner surface of the first mentioned pair of opposed walls from the upper end of the passageway and connected at their lower ends to the headers adjacent these respective walls, the tubes forming the superheater tube bundle having portions extending down past the economizer sections adjacent said first mentioned opposed walls and connected with the headers adjacent these walls, and means supporting the tubes extending down along the walls of the passageway from their upper ends.

5. The organization of claim 4 wherein the headers are connected together and wherein the economizer sections are effectively supported from the superheater supply tubes with one of the transversely extending portions of each of the elements of the economizer sections being free to flex to accommodate differential movement.

6. The organization of claim 5 wherein the superheater supply tubes are spaced the width of a tube with said space down to the lower end of the superheater tube bundle-being filled with fins extending laterally from the tubes and with said space below said superheater tube bundle being filled with tubes from said bundle.

References Cited in the file of this patent UNITED STATES PATENTS 2,357,300 Bailey Sept. 5, 1944 2,553,493 Woolley May 15, 1951 2,599,316 Boyer June 3, 1952 2,681,641 Andrews et al. June 22, 1954 

